Version May 2024
INTRODUCTION — Bone sarcomas are malignant mesenchymal-derived bone tumors that are of many different subtypes. (See 'Histologic classification' below.)
Osteosarcoma is the most common primary malignant tumor of bone. Osteosarcomas are characterized by the production of osteoid or immature bone by the malignant cells [1-3]. Osteosarcomas are uncommon tumors compared with carcinomas, with approximately 900 cases diagnosed each year in the United States, mainly in children and adolescents [4]. Among 15- to 29-year-olds, bone tumors account for 3 percent of all tumors, and osteosarcoma accounts for approximately one-half of these cases [5]. Most osteosarcomas present as high-grade tumors and most are located around the anatomic regions of high growth rate.
The survival of patients with malignant bone sarcomas has improved dramatically over the past 30 years, largely because of chemotherapeutic advances. Before the era of effective chemotherapy, 80 to 90 percent of patients with osteosarcoma developed metastatic disease despite achieving local control from surgery and died of their disease. It was surmised (and subsequently demonstrated [6]) that the majority of these patients had subclinical metastatic disease that was present at the time of diagnosis, even in the absence of overt metastases.
In osteosarcoma, chemotherapy can successfully eradicate microscopic deposits in the majority of cases if initiated at a time when the disease burden is low (ie, following resection of the primary tumor). As a result, all patients with intermediate- or high-grade osteosarcoma receive chemotherapy, although the optimal timing (ie, preoperative or postoperative) is controversial [7]. Low-grade osteosarcomas, such as parosteal osteosarcomas, are not treated routinely with chemotherapy because the risk of metastasis is low. (See 'Adjuvant therapy' below.)
With modern therapy, approximately two-thirds of patients with non-metastatic extremity osteosarcoma will be long-term survivors, up to 50 percent of those with limited pulmonary metastases may be cured of their disease, and long-term relapse-free survival can be expected in approximately 25 percent of those who present with metastatic disease overall [8-12].
Surgical management has evolved in parallel with the emergence of effective chemotherapy. Although complete extirpation of the tumor remains the primary objective, the nature and scope of the approach taken to accomplish this goal has changed, with an emphasis on more conservative surgery in order to maintain function. Functional outcome depends not only on the extent of resection and the amount of muscle that is removed but also on the quality of the reconstruction and its associated complications. Limb-sparing surgery rather than amputation is now possible in most patients, particularly when preoperative (neoadjuvant) chemotherapy is used.
Here we will discuss the principles of surgical management for primary bone sarcomas. Although the focus of this topic review will be on osteosarcoma, most of the same surgical principles apply to other bone sarcomas as well. Intermediate or high-grade fibrosarcoma of bone and undifferentiated high-grade pleomorphic sarcomas, previously termed malignant fibrous histiocytoma of bone (table 1) [13], are treated in a similar manner as osteosarcoma. Other bone sarcomas, such as leiomyosarcoma and chondrosarcoma, may be managed with a slightly different approach because of differences in their responsiveness to chemotherapy and radiation therapy. As an example, neoadjuvant chemotherapy is usually not considered routine for chondrosarcomas because they are relatively chemoresistant. Leiomyosarcoma of bone has typically been treated in a similar manner to that of the leiomyosarcoma in soft tissues. In contrast, Ewing sarcoma is usually approached initially with systemic chemotherapy due to its chemosensitivity. Radiation therapy and/or surgery may be used to aid in local control for Ewing sarcoma. (See "Overview of multimodality treatment for primary soft tissue sarcoma of the extremities and superficial trunk" and "Treatment of locally recurrent and unresectable, locally advanced soft tissue sarcoma of the extremities" and "Treatment of Ewing sarcoma" and "Chondrosarcoma".)
Surgery can be a component of management of metastatic disease both at initial presentation and at the time of recurrence, and is addressed elsewhere. (See "Chemotherapy and radiation therapy in the management of osteosarcoma", section on 'Potentially resectable disease' and "Treatment of Ewing sarcoma", section on 'Local treatment'.)
PREOPERATIVE EVALUATION — The goal of the preoperative evaluation is to establish the tissue diagnosis, evaluate disease extent, and assess the feasibility of a limb-sparing approach. Clinical staging includes all the data obtained prior to definitive therapy, including the results of imaging, physical examination, laboratory studies, and tissue biopsy. (See "Clinical presentation, staging, and prognostic factors of Ewing sarcoma" and "Osteosarcoma: Epidemiology, pathology, clinical presentation, and diagnosis".)
A thorough history and physical examination that evaluates all systems is necessary prior to definitive treatment. The history needs to include prior radiation exposure and other possible reasons for secondary osteosarcomas such as Paget disease [14]. However, physical examination should focus particularly on the involved bone or joint. The regional lymph nodes (although they are a rare site for metastases), other bones (sometimes synchronous but may be the site for distant disease), and lungs (the most common metastatic site) are sites for disease dissemination.
Radiographic imaging — Plain radiographs are a good way to begin to evaluate a bone lesion, as they provide data that often cannot be replicated even with magnetic resonance imaging (MRI) or computed tomography (CT). Nonetheless, although plain radiographs can often predict the probable histology of a potentially malignant bone lesion, the definition of tumor size and local intraosseous and extraosseous extent is most accurately achieved by MRI. The entire involved bone should be imaged to avoid missing skip metastases (ie, medullary disease within the same bone, but not in direct contiguity with the primary lesion) (image 1).
CT scans are best suited to evaluate the thorax for metastatic disease, which is essential because approximately 80 percent of metastatic lesions in osteosarcoma occur in the lungs [15,16]. The most common metastatic site for all bone sarcomas is pulmonary. Thin-section imaging of the chest using high-resolution helical CT is the preferred modality, detecting approximately 20 to 25 percent more nodules than conventional CT, and the reliable detection of nodules as small as 2 to 3 mm. (See "Surgical resection of pulmonary metastases: Benefits, indications, preoperative evaluation, and techniques", section on 'Computed tomography'.)
Radionuclide bone scanning with technetium and integrated positron emission tomography (PET)-CT are options to evaluate the entire skeleton for the presence of multiple lesions and "skip" metastases [17]. Guidelines from the National Comprehensive Cancer Network (NCCN) [18] suggest a PET scan and/or bone scan in the workup of suspected osteosarcoma, and imaging guidelines from the Children's Oncology Group Bone Tumor Committee for both osteosarcoma and Ewing sarcoma recommend radionuclide bone scan and/or PET scan for whole body staging. This subject is addressed in detail separately. (See "Osteosarcoma: Epidemiology, pathology, clinical presentation, and diagnosis", section on 'Evaluation for systemic disease' and "Clinical presentation, staging, and prognostic factors of Ewing sarcoma", section on 'Metastatic work-up'.)
Tissue biopsy — A biopsy of the tumor completes the staging process. As with soft tissue sarcomas, the biopsy must be carefully planned to ensure adequate tissue is obtained for diagnosis without compromising the opportunity for limb salvage. Biopsies should take place after the completion of the staging studies, and the surgeon, radiologist, and pathologist should review these studies in detail so that each member of the team is fully appraised of the diagnostic considerations.
Either a core needle or open biopsy may be performed if adequate tissue is obtained. For CT-guided core biopsies, multiple cores of tissue should be obtained for rapid on-site evaluation, using touch preparation cytology or, for frozen section (to ensure that adequate tissue has been obtained), permanent hematoxylin and eosin (H&E) stained sections, and microbial culture (in case the diagnosis should turn out to be osteomyelitis), and one core is reserved for special stains or cytogenetic studies. (See "Bone tumors: Diagnosis and biopsy techniques", section on 'Specimen handling'.)
Although fine needle aspiration biopsy under radiologic guidance may obviate the need for open biopsy, the risk of a nondiagnostic or nonrepresentative sample must be considered [19]. In one report of 359 patients with musculoskeletal lesions, the accuracy rates of CT-guided biopsies and fine needle aspirates were 74 and 63 percent, respectively [20]. (See "Bone tumors: Diagnosis and biopsy techniques", section on 'Planning the biopsy'.)
If an open biopsy is performed, the incision should be placed in accordance with the planned surgical resection; the primary tumor and the entire biopsy tract should be resected en bloc. Meticulous hemostasis and the judicious use of a drain are important to avoid the spread of hematoma-containing tumor cells. If a soft tissue mass is not present, or material is nondiagnostic, a bone defect may be required to obtain tissue. If so, it should be a small, oval defect, and a polymethylmethacrylate plug may be used to close the hole to minimize hematoma. (See "Bone tumors: Diagnosis and biopsy techniques", section on 'Operative biopsy'.)
Tumor staging — The staging system used primarily for bone sarcomas was developed by Enneking et al at the University of Florida and based on a retrospective review of cases of primary malignant tumors of bone treated by primary surgical resection (table 2) [21,22]. This system characterizes nonmetastatic malignant bone tumors by grade (low grade [stage I] versus high grade [stage II]), and further subdivides these stages according to the local anatomic extent. The compartmental status is determined by whether the tumor extends through the cortex of the involved bone. Patients with distant metastases are categorized as stage III.
The American Joint Committee on Cancer (AJCC) adopted a similar staging system in its 1997 fifth edition [3]. The latest 2017 modification from the joint AJCC/Union for International Cancer Control (UICC) has separate and distinct tumor, node, metastasis (TNM) classifications for primary tumors arising in the appendicular skeleton/trunk/skull/facial bones and those arising in the pelvis and spine (table 3) [23].
The TNM classification has not been widely used for primary bone tumors, particularly for Ewing sarcoma, since it does not take into account several important clinicopathologic features, such as primary tumor site, patient age, and histology. The staging classification used for Ewing sarcoma is complex and discussed in detail elsewhere. (See "Clinical presentation, staging, and prognostic factors of Ewing sarcoma".)
HISTOLOGIC CLASSIFICATION — Primary bone sarcomas are classified according to their cytologic features and matrix produced (eg, osteoid). The different types of osteosarcomas are briefly described here. For other sarcomas of bone (eg, chondrosarcoma), subtypes exist as well, based on the histology (see "Chondrosarcoma" and "Chordoma and chondrosarcoma of the skull base"). The histologic appearance of the Ewing sarcoma family of tumors is described elsewhere. (See "Epidemiology, pathology, and molecular genetics of Ewing sarcoma", section on 'Histologic features'.)
The diagnosis of a primary bone malignancy should be rendered only in the setting of radiologic studies, including plain films and magnetic resonance imaging (MRI) or computed tomography (CT) of the primary lesion. While radiologic or histologic findings may not be specific by themselves, a histologic diagnosis in the context of consistent radiographic findings secures the diagnosis with much greater certainty.
The histologic diagnosis of an osteosarcoma depends on the presence of malignant sarcomatous tumor cells associated with the production of osteoid matrix or bone. Osteosarcomas are thought to arise from a mesenchymal stem cell that is capable of differentiating towards fibrous tissue, cartilage, or bone. As a result, they share many features with chondrosarcomas and undifferentiated pleomorphic sarcomas of bone. However, chondrosarcomas and undifferentiated pleomorphic sarcomas of bone are distinguished by their lack of osteoid matrix, which is required for the diagnosis of osteosarcoma (table 4). Of note, the degree of osteoid production in osteosarcomas may be limited.
The largest group of osteosarcomas are conventional (intramedullary high grade) osteosarcomas, which account for approximately 90 percent of all osteosarcomas [24]. These tumors usually involve the metaphysis of long bones in adolescents and young adults (figure 1).
Conventional osteosarcomas can be classified as osteoblastic, chondroblastic, or fibroblastic, depending on the predominant cellular component; all are managed similarly if they are of the same grade:
●Osteoblastic osteosarcoma, which accounts for 50 percent of cases, is characterized by abundant osteoid production, which forms a fine or coarse lacelike pattern around the tumor cells; massive amounts may result in distortion of the malignant stromal cells. Some tumors contain thick trabeculae of osteoid that form an irregular anastomosing network. The amount of mineralization is variable.
●Fibroblastic osteosarcomas are predominantly composed of a high-grade spindle cell stroma that contains only focal osteoid production. More pleomorphic tumors may resemble undifferentiated high-grade pleomorphic sarcomas of bone (previously termed malignant fibrous histiocytoma of bone [13] ), but the distinction can be made by the identification of osteoid.
●In chondroblastic osteosarcomas, cartilaginous matrix production may be evident throughout most of the tumor or only in certain locations, underscoring the heterogeneity of these tumors. These chondroblastic foci are admixed with malignant spindle cells that produce osteoid matrix.
In addition to the three categories of conventional osteosarcoma, there are two variants (ie, the telangiectatic and small cell subtypes) that were originally thought to carry a worse prognosis. However, with modern aggressive therapy, they behave in general like conventional osteosarcomas and are treated similarly:
●Small cell osteosarcoma is noteworthy for the confusion that may arise in distinguishing it from other "small blue round cell tumors" such as Ewing sarcoma by conventional light microscopy of hematoxylin and eosin (H&E) stained sections [25]. Immunohistochemical staining, cytogenetics, and molecular genetic studies may be required to establish the diagnosis. (See "Treatment of Ewing sarcoma".)
●Telangiectatic osteosarcoma has a purely lytic appearance on plain radiographs, and there is a high rate of pathologic fracture [26]. Grossly, these tumors appear like a "multicystic bag of blood"; a solid mass of tumor is usually absent [24]. Telangiectatic osteosarcomas have overlapping features with aneurysmal bone cysts and giant cell tumors. However, the cells are highly pleomorphic, unlike the benign appearance of the aneurysmal bone cyst. Because they often contain minimal osteoid and numerous multinucleated giant cells, they may be mistaken for a giant cell tumor. Although once thought to carry a poorer prognosis than conventional osteosarcomas, more recent series indicate similar survival with multimodality therapy [26,27]. (See "Giant cell tumor of bone" and "Nonmalignant bone lesions in children and adolescents", section on 'Aneurysmal bone cyst'.)
Undifferentiated pleomorphic sarcoma of bone (previously referred to as malignant fibrous histiocytoma of bone) has an appearance similar to osteosarcoma, but without osteoid production. Although these tumors tend to have a lower rate of tumor necrosis following induction chemotherapy, long-term survival rates for intermediate and high-grade undifferentiated pleomorphic sarcomas of bone are similar to conventional osteosarcomas [28], with the possible exception of spine primaries [29].
With very careful examination, occasionally osteoid will be found in rare sections of tumor, suggesting that this subtype of primary bone tumor may represent an undifferentiated version of a more classic osteosarcoma. (See "Clinical presentation, histopathology, diagnostic evaluation, and staging of soft tissue sarcoma", section on 'Histopathology'.)
Surface or juxtacortical osteosarcomas differ as a group with respect to prognosis and therapy. These osteosarcomas include the following [30-32]:
●Parosteal osteosarcoma, a low-grade osteosarcoma
●Periosteal osteosarcomas, which are usually chondroblastic, intermediate-grade tumors (image 2)
●Rare high-grade surface osteosarcomas
Among the surface osteosarcomas, surgery alone may be curative, particularly for tumors that are low-grade and do not enter the marrow cavity [33,34]. However, at least some data support the benefit of adjuvant chemotherapy in periosteal and high-grade surface osteosarcomas [32]. Given the rarity of this diagnosis, it is worthwhile obtaining a second opinion regarding the pathology and radiology for such tumors at expert centers.
Because of the rarity of osteosarcoma in adults, other cancers should be considered in the differential diagnosis, such as primary lymphoma of bone and metastatic carcinoma, in addition to the primary bone tumors discussed above.
Besides osteosarcomas, undifferentiated pleomorphic sarcomas, and chondrosarcomas, other less common primary bone tumors include primitive neuroectodermal tumor/Ewing sarcoma, chordomas, angiosarcomas (a subtype with a particularly high rate of metastatic disease at presentation [35]), and a variety of other rare tumor types. Histologic characteristics of the Ewing sarcoma family of tumors are discussed elsewhere. (See "Epidemiology, pathology, and molecular genetics of Ewing sarcoma", section on 'Histologic features'.)
SURGICAL MANAGEMENT OF THE PRIMARY TUMOR — Despite the favorable response of osteosarcomas to chemotherapy (see 'Chemotherapy' below), surgery is a necessary component of curative therapy [36]. The specific surgical procedure is dictated by the location and extent of the primary tumor [37]. Axial tumors tend to do worse probably because they are larger when discovered and more difficult to resect. Although all patients with extremity sarcomas are candidates for amputation, emphasis on functional outcome has focused efforts on limb-sparing procedures. However, not all patients are candidates for more conservative surgery (see 'Patient selection' below). In order to avoid sacrificing oncologic outcome, tumor control must be the primary therapeutic concern, and functional outcome a secondary goal. One of the most important tasks of the preoperative evaluation is to assess the feasibility of performing a limb-salvage procedure based on the clinical presentation and disease extent. (See 'Preoperative evaluation' above.)
Types of resections — Bone resections fall into one of three categories, depending on the anatomic site and the extent of the involved bone that needs to be excised. Because most bone sarcomas arise in the metaphysis of the long bones near a joint (figure 2), the majority of resections, for tumors in the lower extremity, include both the segment of tumor-bearing bone and the adjacent joint (osteoarticular resection). Most often, the incision is performed through the joint (intraarticular resection); however, when the tumor extends along the joint capsule or ligamentous structures or invades the joint, the entire joint can be resected (extraarticular resection) to avoid cutting through tumor.
Less frequently, tumor arises within the diaphysis or shaft region of a long bone, and the bone alone is resected (an intercalary resection). Uncommonly, extensive involvement along the length of the bone precludes adequate resection and reconstruction without sacrificing the entire bone, and a whole bone resection, including both proximal and distal joints, is required.
Resection margins — An important consideration in selecting the type of operation is the ability to attain a negative margin of resection with the planned surgical procedure. The quality of the tissue forming the margin is as important as the distance between tumor and uninvolved tissue. The Musculoskeletal Tumor Society recognizes a wide local excision either by amputation or a limb-sparing procedure as the recommended surgical approach to bone sarcomas [38]. The wide local excision removes the primary tumor en bloc along with its reactive zone and a cuff of normal tissue in all planes. However, in many cases, particularly for tumors involving the spine, wide local excision cannot be accomplished easily. An "intralesional" surgical resection margin is more frequently obtained during a procedure that removes the tumor in a piecemeal fashion or by curettage, while a "marginal" resection margin refers to a situation where the pseudocapsule and reactive zone surrounding the tumor form the surgical margin. These operations may result in residual tumor cells being left behind.
Computer navigation is beginning to be used to aid with complex surgical resections that are difficult to accomplish using two-dimensional imaging alone. Computer-assisted tumor surgery (CATS) facilitates three-dimensional surgical planning preoperatively and guides the planned bone resection intraoperatively to achieve an optimal margin [39-41]. The technique may be particularly useful for resection of difficult pelvic or sacral tumors, for limiting resection of normal bone in joint-preserving tumor surgery, or for reconstruction of bony defects using prostheses or allografts [39].
Extremity lesions: Limb-sparing procedures — For lesions involving either the upper or lower extremity, limb salvage can improve functional outcome without sacrificing local disease control as long as complete tumor resection is anatomically possible and adjuvant chemotherapy is used [12,42,43]. Although the functional results are generally better, the available data do not support the position that quality of life or long-term psychosocial outcome is substantially superior after limb salvage than after amputation [44-49]. There is, however, a higher complication rate in patients who undergo limb salvage as compared with amputation [44,50].
Despite the increasing numbers of limb salvage procedures, there are no randomized prospective studies that prove its oncologic safety compared with amputation. However, retrospective series with long-term follow-up of patients with osteosarcoma who undergo amputation or limb salvage do not show a difference in overall or disease-free survival [51]. Nevertheless, appropriate patient selection is critical (see 'Patient selection' below). If there is any doubt that a wide local excision can be accomplished, amputation, the oncologic "gold standard," is the indicated procedure in order to avoid local recurrence, which is invariably followed by metastatic tumor spread and diminished survival [52-55].
Compared with amputation, limb salvage procedures are usually associated with narrower surgical margins, which can increase the likelihood of a local failure [53,56]. The degree of chemotherapy-induced tumor necrosis and surgical margin status are the important prognostic factors for local control [54,57]. For patients undergoing neoadjuvant chemotherapy in order to increase the feasibility of a limb-sparing procedure, it is unclear whether the reduction in surgical margins afforded by a favorable antitumor response increases the likelihood of a local recurrence. The available data are contradictory. Several multicenter series suggest an increased risk of local recurrence, even in patients with a good response to chemotherapy [54,56,58], while other single institution studies indicate similar local recurrence rates for limb-sparing and amputation procedures [53,57].
Patient selection — Tumor location and extent are the most important determinants of the feasibility of limb-sparing surgery. Among the contraindications for limb-sparing surgery are nerve and/or vessel encasement by tumor, the presence of a large biopsy-related hematoma, and possibly the presence of a pathologic fracture.
Pathologic fracture — The available data suggest that patients with osteosarcoma who present with or sustain a pathologic fracture have a higher rate of local recurrence and an increased risk of death relative to those who do not have a pathologic fracture [59]. However, the method of local control, whether limb salvage or amputation, does not appear to impact the ultimate outcome of these patients.
A pathologic fracture is present at diagnosis or occurs during the course of treatment in 5 to 10 percent of patients with osteosarcoma (image 3). Historically a pathologic fracture was considered an indication for immediate amputation because of the theoretical presence of tumor cells within the hematoma, and a greater risk of both local recurrence and shorter survival with limb-sparing procedures [60-64]. However, data suggest that limb salvage is possible with an acceptable rate of local control:
●A multi-institutional series from the Musculoskeletal Tumor Society compared outcomes for 52 patients with osteosarcoma and a pathologic fracture versus those in 55 concurrently treated patients, matched for age and tumor location, who had an osteosarcoma without a pathologic fracture [60]. Overall, both five-year overall (55 versus 77 percent) and local recurrence-free survival rates (75 versus 96 percent) were significantly poorer for those presenting with a pathologic fracture. However, there were no significant differences in outcome when limb salvage was compared with amputation in patients with a pathologic fracture: 11 of 30 patients managed with limb salvage (37 percent) versus 10 of 22 who underwent amputation (45 percent, p = 0.05) died of their disease.
●A single-institution retrospective review compared outcomes of 31 patients with high-grade osteosarcoma who presented with a pathologic fracture versus 201 patients without a pathologic fracture [65]. In the pathologic fracture group, 19 patients had limb-salvage surgery (61 percent), while 12 underwent an amputation; limb-salvage surgery was performed in 86 percent of the non-fracture group. Five-year overall survival was significantly worse for patients presenting with a pathologic fracture (41 versus 60 percent), but there was no difference in local recurrence rate after limb-sparing surgery in the pathologic fracture versus no-fracture group (10 versus 8 percent).
●A systematic review and meta-analysis examined the prognostic impact of pathologic fracture in eight studies totaling 1464 patients with osteosarcoma that compared outcomes in those with and without a pathologic fracture at diagnosis; the two studies described above were included in the analysis [66]. While five-year event-free survival (EFS) rates were lower in those with a pathologic fracture (pooled estimate of five-year EFS 49 versus 67 percent, relative risk [RR] 1.33, 95% CI 1.12-1.59), local recurrence rates were not significantly higher (pooled estimate 14.4 versus 11.4 percent, hazard ratio [HR] for local recurrence 1.39, 95% CI 0.89-2.20). Furthermore, among the 171 patients from six studies who had a pathologic fracture at diagnosis, rates of local recurrence were similar in those treated by amputation or limb salvage (pooled estimate 14.9 versus 14 percent, HR 0.89, 95% CI 0.43-1.83).
After the pathological fracture heals, which may even happen during neoadjuvant chemotherapy, limb-salvage surgery may usually be undertaken safely and under better circumstances than at the time of fracture, as long as wide surgical margins can be achieved. In many of these series, the majority of patients were treated with limb-sparing approaches, and the presence of a pathologic fracture did not constitute a negative prognostic factor for either local recurrence or survival [61,67]. Despite these data, many investigators classically still consider a pathologic fracture to be a relative rather than an absolute contraindication to limb-sparing procedures. At least a discussion with the family or other caregivers should be undertaken discussing limb salvage versus amputation.
Indications for amputation — In certain circumstances, amputation or rotationplasty (see 'Rotationplasty and the skeletally immature patient' below) may be preferred over limb-sparing surgery for extremity sarcomas. Prosthetic improvements have enhanced the amputee's functional results. Furthermore, some types of amputation do not require the patient to wear a prosthesis, and they are associated with lesser cosmetic and functional deformity as compared with those individuals who have undergone an amputation and need a prosthesis to return to the normal activities of daily living.
As in dental implants, a stem can be inserted into the residual bone, which in turn is left long to penetrate the skin. The implant then connects to the external prothesis. This technique was developed in Sweden and is particularly beneficial in circumstances when the bone residue is short [68-70]. There are potential problems with infection around the region where the implant penetrates the skin. However, there are also benefits. As an example, the forces transmitted through the bone may help reduce phantom sensations.
Although amputation does not preclude a local recurrence, the risk is less than 5 percent. Stump recurrence has been attributed to extensive intramedullary tumor spread and the existence of skip lesions. It is important to assess the joint that is adjacent to the primary extremity sarcoma to determine whether an intraarticular or extraarticular resection will be necessary and to exclude the presence of skip metastases within the involved bone (image 1). Among the factors that lessen the likelihood of local recurrence are a wide surgical margin and a good histologic response to neoadjuvant therapy [54]. (See 'Chemotherapy' below.)
Rotationplasty and the skeletally immature patient — Growth considerations following resection and reconstruction are not a major concern for patients with lower extremity lesions who are at or near skeletal maturity or for lesions involving the upper extremity. However, for skeletally immature children with lower extremity lesions, vigorous functional demands and limb length inequality following a limb-sparing procedure is a major problem. In this setting, surgical options include rotationplasty, amputation, or reconstruction with an expandable metal endoprosthesis. (See 'Allografts and endoprostheses' below.)
The Van Ness rotationplasty is a surgical technique for lesions involving the femur that was originally described in 1930. It involves resection of the tumor and surrounding tissues as an intercalary amputation, saving only the sciatic nerve, while either twisting and curling the femoral vessels or segmentally resecting a portion of the vessels with a subsequent vascular anastomosis [71-73]. Typically, the distal femur and its adjacent musculature are excised, and the tibia and foot preserved by maintaining an intact neurovascular bundle. The tibia is then fixed with plates and screws to the proximal femur, and the distal extremity rotated 180º, permitting the foot and ankle to function like a knee (picture 1). The vessels adjacent to the tumor can be resected and reanastomosed if necessary. The retained foot acts as the amputation stump for a transtibial amputation, and this prosthetic arrangement requires less energy expenditure than that required for a transfemoral amputation.
Although the appearance of the reconstructed limb is cosmetically displeasing, the major advantage of rotationplasty in the skeletally immature patient is the ability to tailor the limb length at maturity. Functional results are excellent, with patients able to achieve recreational, sporting, and career goals [74].
A series of 25 children treated with rotationplasty focused on risk factors for failure and postoperative complications [75]. The majority of cases (22 of 25) produced excellent functional outcome. The few failures were a result of vascular impairment by the tumor, necessitating amputation. Patients with larger tumors, unresponsiveness to chemotherapy, or a preoperative pathologic fracture appeared to be at higher risk of failure.
In view of these favorable functional results, rotationplasty is often the reconstructive procedure of choice for children under the age of eight who have proximal lower extremity sarcomas. However, some patients and their families or other caregivers refuse rotationplasty and amputation, and allografts are frequently used to reconstruct the defect in the skeletally immature patient, with standard limb equalizing procedures carried out at a later date. An alternative to allografts is the use of expandable or modular metal prostheses, which can be lengthened as the child grows. All of these approaches have limitations, and their advantages and disadvantages in very young patients are discussed below. (See 'Reconstruction techniques' below.)
Upper extremity lesions involving the shoulder — Tumors of the scapula present an unusual challenge. Although subtotal or complete scapulectomy can be considered for some lesions [76,77], limb reconstruction is difficult and shoulder morbidity may be substantial. For massive tumors of the shoulder girdle (including the proximal humerus), the Tikhoff-Linberg (interscapulothoracic) resection is an alternative to forequarter amputation as long as resection of the brachial plexus is not necessary [78]. The proximal humerus and scapula are resected without the need for bony replacement, and the function of distal arm, elbow, and hand is preserved. Because the resulting shoulder region is unstable, with telescoping of the intervening structures when stresses are applied to the hand or forearm, stabilization is necessary using Dacron tape. This is usually sufficient to prevent telescoping and stress to the remaining neurovascular structures. When the scapula can be preserved, an arthrodesis with or without allograft can be attempted even if the surrounding deltoid and rotator cuff musculature requires resection.
Non-extremity lesions — The principles derived from extremity sarcoma resections have now been applied to the axial structures. Osteosarcomas involving the axial skeleton have a worse prognosis than those involving the extremities, in part due to the difficulty in achieving complete surgical resection in these difficult locations [79-81]. In particular, primary malignant non-extremity tumors are more difficult to resect secondary to their large size, surrounding neurologic and vascular structures, reconstructive challenges, and frequent comorbidities. For complex cases, such as pelvic or sacral tumors, CATS may facilitate three-dimensional surgical planning and guide bone resection with improved surgical accuracy [39]. (See 'Resection margins' above.)
Pelvic and spine tumors are associated with unique challenges. In the spine, en bloc resections may be intralesional, marginal, or wide. Radical resections or removing the entire epidural space is not feasible. The dura and epidural space offer a unique region for tumor management.
Pelvic tumors — Pelvic tumors represent a unique challenge. A tumor arising in the pelvis can involve a segment of nonarticular bone, the acetabulum, or both. En bloc excision of the hemipelvis with preservation of the extremity (internal hemipelvectomy) produces equivalent oncologic results when compared with external formal hemipelvectomy (hindquarter amputation) and better functional outcome [82,83]. It is preferred over external hemipelvectomy, usually because of patient preference.
External hemipelvectomy may be necessary in up to one-third of patients, and despite this, local recurrence rates are high because of difficulty obtaining adequate margins [84-87]. In a large series of 67 patients with pelvic osteosarcoma, 50 underwent surgical excision, 12 of whom required external hemipelvectomy; the remainder had limb-sparing procedures [86]. The incidence of local recurrence overall was 70 percent, and it was 62 percent for those undergoing definitive surgery. Despite the use of multiagent systemic chemotherapy, the five-year overall and progression-free survival rates were only 27 and 19 percent, respectively. Postoperative radiation therapy (RT) improved the outcome for patients with an intralesional or no surgical excision.
Internal hemipelvectomy has been combined with intraoperative RT in an attempt to improve local control [88]. Initial results are promising, but further clinical experience is needed.
The extent of resection determines the functional deficit and influences the decision regarding the type of reconstruction, if any, to optimize function. An internal hemipelvectomy may not require allograft or a metallic endoprosthesis reconstruction. Resection without reconstruction is a reasonable option, particularly in view of the high complication rate with reconstruction of pelvic defects using allografts (approximately 50 percent) [89]. The femur and remaining pelvis can be left flail and the gap is bridged by scar tissue, or postoperative traction can be applied to initiate the development of scar tissue. Although this allows for relatively stable weight bearing, it also results in a significant limb length inequality, and most patients require crutches for ambulation. The large length discrepancy is disliked by all patients, and moreover, the subsequent pain that develops in contralateral joints can be worse than the surgical site.
Metallic endoprosthesis reconstruction (saddle prosthesis) has occasionally been successful, but fixation is extremely difficult and prosthesis loosening can be a problem long-term [83,90,91]. Another method of obtaining structural integrity is to fuse the proximal femur to the ilium or sacrum [92]. The choice of procedure is dependent on the clinical situation and the surgeon and patient preference, but they in general offer reasonable alternatives to external hemipelvectomy, with superior functional and psychological results.
Spine tumors — The spine presents a particularly difficult problem with regard to surgical margins. Local recurrence rates are closely tied to surgical margin status [79,93]. In one report of 30 patients with primary sarcomas of the mobile spine, the resection was classified as wide, marginal, or intralesional in 23, 10, and 67 percent respectively [94]. Resection margins were histologically positive in 60 percent and associated with a fivefold increased risk of a local recurrence. At least one series suggests an advantage for either wide or marginal surgery compared with intralesional or no surgery for osteosarcomas of the spine [79]. They recommended that these patients be treated with a combination of chemotherapy and at least marginal surgery.
En bloc resection (vertebrectomy) followed by stabilization and fusion is possible with wide margins in some cases as long as dural invasion is absent. If the tumor abuts or invades the dura (image 4), a segment can be excised. However, this procedure may be accompanied by seeding of tumor cells into the cerebrospinal fluid. Postoperative (adjuvant) RT can be employed to manage a microscopically positive dural margin. Largely because of the potential for dural involvement, local recurrence rates are higher for tumors located in the vertebral body and posterior elements (particularly those with extra-osseous extension into the canal and paraspinal region) as compared with the anterior vertebral column.
Patients with sacral tumors do especially poorly. In one report that included 22 patients with primary high-grade osteosarcoma of the spine or sacrum, all of whom received neoadjuvant chemotherapy, only 2 of the 12 who underwent surgery had wide excision to negative margins [79]. Although total sacrectomy may improve local control, neurologic and sexual dysfunction is inevitable [95]. Local recurrence may still develop despite maximal surgical resection and intraoperative or postoperative RT [80,88].
Postoperative RT may be beneficial [79]. Newer methods of adjuvant RT, including combined proton beam and photon irradiation using three-dimensional conformal techniques, may permit a higher dose of radiation to be administered while sparing adjacent normal tissues [96]. (See "Treatment of Ewing sarcoma".)
Allograft reconstruction is an effective means of filling the massive osseous defects following spine resection. Combined anterior and posterior instrumentation provides the best stability following tumor vertebral body resection. In the anterior spine, femoral and humeral shafts used to substitute for resected vertebral bodies have provided excellent stability. Metal cages provide an alternative to allografts in the anterior spine, and they do not require biologic healing of the graft to the host bone [97]. New posterior instrumentation, bone graft products, and pedicle screws provide improved fixation and better rates of fusion. In setting where RT has been used to improve local control, complications such as fractures and non-unions may occur more frequently. The bridging of a large osseous defect may also be augmented with vascularized grafts. (See 'Vascularized grafts' below.)
RECONSTRUCTION TECHNIQUES — The majority of patients with osteosarcoma will require reconstructive procedures to restore structural integrity. However, some locations and circumstances do not always require reconstruction to deal with the surgical defect. As an example, pelvic tumors may not require postresection reconstruction following an internal hemipelvectomy (see 'Non-extremity lesions' above). Expendable bones that do not require replacement include the ulna, patella, fibula, scapula, and ribs. Resection techniques for tumors in these locations are well described, and the resultant functional disability without bony reconstruction is frequently minimal with the exception of complete scapulectomy, which may result in significant morbidity, especially if muscle loss is great.
For patients who do require reconstruction, available methods include metal endoprostheses/hardware, allografts, arthrodeses, vascularized fibular transfers, rotationplasty, and various unusual methods that are specific for certain anatomic locations. The choice of reconstructive method should be individualized. The following factors influence the selection of a reconstructive method [98]:
●Anatomic location and integrity of the surrounding structures
●The stage of disease and extent of resection
●The tissue diagnosis
●Preference of the surgeon
●The likelihood and nature of complications related to a particular type of reconstruction
●The patient's age, expectations, and anticipated functional demands
●The availability of the materials for the reconstructive procedure
Because the majority of patients receive preoperative (neoadjuvant) chemotherapy, planning of the surgical procedure is essential in order to coordinate chemotherapy schedules and anticipated bone marrow recovery with the time needed to manufacture a prosthesis or procure the necessary reconstructive materials.
An understanding of the capabilities and limitations of available reconstructive techniques is necessary so that the appropriate method is chosen for the surgical reconstruction. A brief description of some of these techniques follows. Rotationplasty is discussed above. (See 'Rotationplasty and the skeletally immature patient' above.)
Allografts and endoprostheses — Allografts and metal endoprostheses are common means of reconstructing bone defects that result from sarcoma surgery. Other methods listed below may be preferred to fill the osseous defect depending on the clinical situation and the availability of the product.
Allografts — While autologous bone grafting is of limited use in patients undergoing resection of bone tumors because of the large size of the defect, allografts have been successfully used for many years. Allografts provide the potential for long-lasting reconstruction of large bony defects by providing a structural lattice for the ingrowth of the patient's own bone elements (image 5) [99-105]. The host normal tissue slowly invades the allograft by creeping substitution of normal bone and vascular elements at the osteosynthesis site and periosteum. Large segments of allografted bone probably do not completely fill with autogenous bone, and this may lead to allograft fracture over time (this occurs in approximately 18 percent of the cases). The articular cartilage is slowly replaced by an inflammatory pannus-like tissue, and some patients may ultimately require joint resurfacing.
Allografts are available from tissue banks and need to be matched to the size of the resected bone. Although bone is a relative nonantigenic structure, matching for the class II major histocompatibility antigens results in better clinical outcomes [106,107]. Freezing further decreases the likelihood of immune rejection, and the addition of glycerol or dimethyl sulfoxide during freezing preserves the articular cartilage somewhat. Soft tissues are left attached to the allograft to increase function by providing a site of attachment for host soft tissues. This is particularly important for reconstructions around the knee.
The major advantages of allografts over endoprosthetic reconstruction are restoration of bone stock, sparing of the uninvolved portion of adjacent joints, and providing a site of attachment for host soft tissues. Intercalary allograft reconstructions tend to perform better than osteoarticular grafts, and clearly better than allograft arthrodeses, which have the highest rate of complications [108].
There are some disadvantages to allografts. Compared with metal endoprostheses, allografts must be fixed to the host bone and allowed to heal. Thus, they must be protected from weight bearing for prolonged periods. Early complication rates (15 to 20 percent) are higher than those seen in patients undergoing placement of metal prostheses. While implant loosening does not occur as it does for metal prostheses, nonunion and fractures may result in allograft failure [109]. As with endoprosthetic reconstructions, infection in the reconstructed site is devastating and may necessitate amputation of the extremity. Late complications include degenerative arthritis and joint instability. Despite these limitations, satisfactory functional results are achieved in 70 percent of patients undergoing allografting [100,104,110,111].
Metal endoprostheses — Initially, the metallic implants that were used to reconstruct bone defects following tumor resection were custom made and manufactured for specific patient requirements. More recently, modular metal prostheses have become available that permit reconstruction without having to resort to a custom implant. The components are readily available and can be assembled at the time of surgery to match the extent of the defect (image 6). Modular metal prosthetic reconstructions are performed most frequently about the shoulder, hip, and knee [112,113]. Total femoral reconstructions have been performed in certain circumstances.
Most bone tumors are located adjacent to joints, and metal endoprostheses are well suited to joint replacement. The implants used for reconstruction after sarcoma surgery are similar to those that are used in patients with arthritis (see "Surgical management of end-stage rheumatoid arthritis"). As compared with allografts, endoprostheses allow for immediate joint stability and early weight bearing. However, they are not free of complications, which include fatigue fracture, loosening, and infection. The fatigue fracture potential of the metal is a design and stress problem that can be potentially improved by manufacturing changes.
Loosening at the bone-cement interface is a function of repetitive stresses during activities of daily living [98,114]. Loosening can be minimized by using a meticulous cementing technique and stress-reducing total joint mechanics such as a rotating-hinge knee design. Nevertheless, most, if not all, implants will need to be replaced at some point in the long-term survivor's lifetime. The survivorship of the prosthetic arthroplasty reconstruction varies, and ranges from 60 to 90 percent estimated survival at 5 years to 40 to 80 percent at 10 years [113,115-117]. These data have generated the impetus for development of cementless or press-fit implants. Implants placed without cement may have a better long term survival, but this is a controversial area.
Because the prostheses act as a large foreign body, infections, which occur in 2 to 5 percent of cases, are difficult to treat [98,113,115,116,118]. Deep infections usually require removal of the implant and sometimes an amputation.
A technological breakthrough in the form of 3D printing has offered new hope for complex reconstructions. Improvements in 3D printing technology allow patients to receive custom limb replacements specifically designed and produced to fit them well. After resection of the bone tumor, the reconstruction process can incorporate synthetic replacements prepared by 3D printing using titanium. They are used as custom implants in multiple anatomic locations [119].
Expandable prostheses — Expandable prostheses have been developed for reconstruction in skeletally immature children with malignant bone tumors [120-122]. Different types of prostheses are available; one type has a telescoping unit that can be expanded using a gear device [122,123], and another employs the principle of a loaded spring that is gradually released via external exposure to an electromagnetic field [124]. Because these devices permit an expansion of the overall length of the prosthesis, they can be implanted in skeletally immature patients, increasing the numbers of those eligible for limb-salvage surgery.
Estimation of growth potential in the younger child is important in determining whether this means of reconstruction is appropriate for the situation. The Lewis Expandable Adjustable Prosthesis (LEAP) was initially successful in young patients (five to eight years). However, newer expandable prostheses that can be lengthened without invasive surgery are popular in this age group. One of these, the Phoenix, uses a magnetic field to provide the energy to lengthen the prosthesis.
The modular prostheses are better for large preadolescent and adolescent children. Most children require several lengthenings in those prostheses, and it is frequently necessary to excise the pseudocapsule around the implant to gain length; as a result, the lengthening procedures are not small operations.
Expandable prostheses frequently require replacement after they have been fully extended because they lose some structural strength. Difficulties in using this prosthesis occur primarily in the rehabilitation phase, but loosening, fatigue failure of the implant, and inability to gain equal limb lengths can also occur. Close follow-up is crucial to optimize the functional outcome and properly time periodic lengthenings.
Allograft-prosthetic composites — For extremity reconstructions, allografts can be combined with metal prostheses (the prosthesis is cemented to the allograft) to form what is called an allograft-prosthetic composite, or alloprosthesis (image 7). This has certain advantages over allografts or metal prostheses alone. Since the articular surface is formed by the metal portion of the construct, it does not fracture or collapse as may happen with osteoarticular allografts. The allograft portion of the composite restores bone stock and provides soft tissue attachment points for insertion of muscle tendons. Even though a great deal of research has been done to improve attachments of muscle units to prostheses, this is still an unsolved problem with this type of reconstruction. Alloprosthetic reconstructions usually result in good or excellent functional results, but the operation is more complex and time consuming than either osteoarticular allografts or prostheses alone [125].
Arthrodesis — Arthrodesis (joint fusion) is important for tumors involving the spine; otherwise, the hardware fails as a result of nonunion, and pain may be a persistent complaint. In the spine almost all fusions require implantation of bone graft material. Transplantation of structured or morselized autologous corticocancellous bone obtained from the iliac crest is the most frequently used technique.
Arthrodesis may also be considered for selected patients with extremity lesions. Although a nonmobile joint is less desirable than a mobile one to the majority of patients, it may provide the best mode of reconstruction in certain cases and is one method by which durable function can be achieved. Arthrodesis of various joints following extraarticular resection of malignant bone tumors may be the best reconstructive option if resection includes most of the surrounding joint soft tissues and joint arthroplasty cannot be accomplished [126,127].
The most common joints that are considered for arthrodeses following resection of bone sarcomas resection are the hip, knee, and shoulder. Hip and shoulder arthrodeses do not produce as much functional disability as knee fusions because of the capacity for excellent compensatory motion at other joints in the affected extremity. Despite functional limitations, knee arthrodesis can be achieved in most patients, even when a long segment of bone has been excised. However, this procedure is complicated by a high incidence of nonunion, fatigue fracture, and infection. Although the operation successfully achieves tumor-free margins, the revascularization and rehabilitation processes are prolonged and complicated. Patients must adjust their lifestyles to accommodate the arthrodesis.
Vascularized grafts — Vascularized bone grafts are also used to reconstruct osseous defects and augment other reconstructive techniques, such as intercalary allograft segments [128,129]. They are of particular benefit in the treatment of allograft nonunions and fractures and in surgical beds, which have poor vascularity and perfusion following radiation therapy. If the vascular graft remains viable, healing occurs more rapidly than with nonvascularized grafts and is a more durable construct.
The surgical procedure for implantation of a vascularized graft is lengthy and the vascular anastomosis is technically demanding. One of the most commonly used grafts for this purpose is the fibula; fortunately, donor site complications are rare. Vascularized fibular grafts have also been used to augment healing of intercalary grafts following intraepiphyseal resections of the distal femur and proximal tibia, where only a short segment of epiphyseal bone remains for fixation.
ADJUVANT THERAPY
Chemotherapy — As previously noted, more than 80 percent of patients with osteosarcoma or Ewing sarcoma treated with surgery alone develop metastatic disease, despite having adequate local tumor control. It is surmised that subclinical metastatic disease is present at diagnosis, even in the absence of overt metastases. Chemotherapy can eradicate these deposits if initiated at a time when disease burden is low. As a result, adjuvant chemotherapy is considered a standard component of management for these primary bone tumors.
For osteosarcoma, postoperative chemotherapy was used initially, and five-year overall survival rates rose from less than 20 percent to between 40 and 60 percent in the 1970s [130]. Two subsequent randomized studies conducted in the 1980s demonstrated a significant relapse-free and overall survival benefit for adjuvant chemotherapy, although the trials were limited in size, and the survival benefits were modest. (See "Chemotherapy and radiation therapy in the management of osteosarcoma".)
For patients with osteosarcoma, neoadjuvant chemotherapy was originally considered because of the time needed for fabrication of custom metallic implants; chemotherapy was given while awaiting definitive surgery. Due to its success in shrinking tumors, neoadjuvant chemotherapy evolved to a method of increasing the proportion of patients who were suitable candidates for limb-salvage surgery and to facilitate limb-sparing procedures by diminishing tumor burden. A major concern in this regard is the possibility that inexperienced surgeons may expand selection criteria to accommodate inappropriate candidates who might be better served by amputation. Adjuvant chemotherapy is never a substitute for sound surgical principles.
One of the most compelling rationales for neoadjuvant chemotherapy is its ability to function as an in vivo drug trial to determine the drug sensitivity of an individual tumor and to customize postoperative therapy. A grading system for assessing the effect of preoperative chemotherapy in osteosarcoma was developed at Memorial Sloan Kettering and is in widespread use (table 5) [130].
The response to neoadjuvant chemotherapy is a major prognostic factor. Patients with a near-complete absence of viable tumor cells in the resection specimen after neoadjuvant therapy do well when the same therapy is continued after surgery. In contrast, if the tumor contains 10 percent or more residual viable cells after neoadjuvant chemotherapy, a change in the chemotherapeutic regimen might be beneficial, although this is a controversial area. This topic is discussed in detail elsewhere. (See "Chemotherapy and radiation therapy in the management of osteosarcoma".)
The majority of limb-sparing surgical procedures for osteosarcoma are performed at institutions using presurgical chemotherapy. On the other hand, immediate resection is an acceptable option in situations where the surgical procedure would not be changed by a good response to neoadjuvant chemotherapy. In such cases, adjuvant chemotherapy should be administered postoperatively.
Issues surrounding the use of neoadjuvant and adjuvant chemotherapy for Ewing sarcoma are also discussed elsewhere. (See "Treatment of Ewing sarcoma".)
Radiation therapy — Unlike Ewing sarcoma, conventional osteosarcoma is relatively resistant to radiation therapy (RT). Because of this, primary RT is not usually adequate to achieve local disease control, particularly for bulky tumors. Issues surrounding the use of RT for Ewing sarcoma are discussed elsewhere. (See "Treatment of Ewing sarcoma".)
There has been renewed interest in a potential role for RT for patients with osteosarcoma whose tumors respond to chemotherapy and in whom surgery would be debilitating. A report described a five-year local control rate of 56 percent among 31 patients with nonmetastatic extremity osteosarcoma who refused surgery and were instead treated with RT (median dose 60 Gy) [131]. No local failures developed in 11 patients who responded well to chemotherapy with both a radiographic and biochemical response (normalization of alkaline phosphatase), and the five-year metastasis-free survival rate was 91 percent. Among patients who achieved local control, 86 percent had "excellent" limb function.
Although local adjuvant RT and prophylactic whole lung RT have been used in an attempt to improve outcomes following surgery, neither is effective in the absence of systemic chemotherapy [15,132,133]. Furthermore, in patients treated with effective surgery and chemotherapy, adjuvant RT does not improve survival and increases the risk for secondary tumors [134]. Adjuvant RT should be considered only in the setting of an unresectable or incompletely resected primary tumor or in patients with the small cell variant of osteosarcoma, which may be more radiosensitive [135].
The role of adjuvant RT in patients with Ewing sarcoma is discussed elsewhere. (See "Treatment of Ewing sarcoma".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Bone cancer (The Basics)" and "Patient education: Chondrosarcoma (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Bone sarcomas – Osteosarcoma is the most common primary malignant tumor of bone; other less common types of bone sarcoma include peripheral primitive neuroectodermal tumor/Ewing sarcoma, undifferentiated high-grade pleomorphic sarcoma of bone (previously termed malignant fibrous histiocytoma of bone), fibrosarcoma, chondrosarcoma, and chordoma. (See 'Histologic classification' above.)
●Preoperative evaluation – The goal of the preoperative evaluation for a primary bone sarcoma is to establish the tissue diagnosis, evaluate disease extent, and assess the feasibility of a limb-sparing approach. Clinical staging includes all of the data obtained prior to definitive therapy, including the results of imaging, physical examination, laboratory studies, and tissue biopsy. The biopsy must be carefully planned to ensure that adequate tissue is obtained for diagnosis without compromising the opportunity for limb salvage. Biopsies should take place after the completion of the staging studies. (See 'Preoperative evaluation' above.)
●Surgical management – Surgery and systemic chemotherapy are the mainstays of treatment for patients with osteosarcomas and other primary bone tumors, such as fibrosarcoma and undifferentiated pleomorphic sarcoma of bone. Chondrosarcoma and chordoma have not been routinely or historically treated with chemotherapy or radiation therapy (RT), and therefore, surgery is the mainstay of management. (See 'Surgical management of the primary tumor' above.)
●Adjuvant therapy
•Chemotherapy – Although there is no specific survival benefit to preoperative as compared with postoperative chemotherapy in osteosarcoma patients, the neoadjuvant approach may permit a greater number of patients to undergo limb-sparing procedures. However, chemotherapy is no substitute for sound surgical judgment when assessing the need for amputation versus limb-sparing surgery. The optimal chemotherapy regimen has not been established. In general, patients with a nearly complete response to neoadjuvant chemotherapy do better than those with a lesser response. Even if the patient has a chemosensitive tumor, it may be reasonable to proceed to immediate surgery followed by adjuvant chemotherapy if the nature of the resection would not necessarily be influenced by a good response to chemotherapy. (See 'Chemotherapy' above.)
•Radiation therapy – There is no role for adjuvant RT except in patients with unresectable or incompletely resected sarcomas and possibly in the rare patient with a small cell osteosarcoma. RT for local control can be used in patients who decline surgery or for whom there is no effective surgical option. However, Ewing sarcoma is more radiosensitive in contrast to osteosarcoma and other primary bone sarcomas, and RT may be considered an effective option for local control. (See 'Radiation therapy' above.)
●Reconstruction – Reconstructive options vary depending on the factors listed above. In addition, there is surgeon preference and no absolute consensus in many circumstances as to the optimal reconstructive method. In some circumstances, if the tumor is located in an expendable bone, reconstruction is not even necessary. (See 'Reconstruction techniques' above.)
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